首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   198篇
  免费   3篇
化学   101篇
晶体学   5篇
力学   2篇
数学   79篇
物理学   14篇
  2023年   1篇
  2022年   3篇
  2021年   6篇
  2020年   3篇
  2019年   6篇
  2018年   8篇
  2017年   5篇
  2016年   3篇
  2015年   6篇
  2014年   12篇
  2013年   16篇
  2012年   11篇
  2011年   17篇
  2010年   13篇
  2009年   12篇
  2008年   10篇
  2007年   5篇
  2006年   6篇
  2005年   7篇
  2004年   7篇
  2003年   5篇
  2002年   8篇
  2001年   6篇
  2000年   2篇
  1999年   2篇
  1998年   1篇
  1996年   1篇
  1992年   1篇
  1989年   1篇
  1988年   1篇
  1985年   2篇
  1984年   1篇
  1983年   1篇
  1982年   1篇
  1981年   3篇
  1978年   1篇
  1976年   1篇
  1975年   1篇
  1971年   1篇
  1960年   3篇
  1958年   1篇
排序方式: 共有201条查询结果,搜索用时 15 毫秒
141.
We use the critical point theory to establish existence results for periodic solutions of some nonlinear boundary value problems involving the discrete p-Laplacian operator. As an application we give an alternative proof to the upper and lower solutions theorem.  相似文献   
142.
We consider a nonlinear nonvariational periodic problem with a nonsmooth potential. Using the spectrum of the asymptotic (as |x| →?∞) differential operator and degree theoretic methods based on the degree map for multivalued perturbations of (S)?+? operators, we establish the existence of a nontrivial smooth solution.  相似文献   
143.
144.
145.
We introduce the notion of induced Hilbert spaces for positive unbounded operators and show that the energy spaces associated to several classical boundary value problems for partial differential operators are relevant examples of this type. The main result is a generalization of the Krein-Reid lifting theorem to this unbounded case and we indicate how it provides estimates of the spectra of operators with respect to energy spaces.  相似文献   
146.
In this paper, we introduce a new iterative process for finding the common element of the set of fixed points of a nonexpansive mapping and the set of solutions of the variational inequality problem for an α-inverse-strongly-monotone, by combining an modified extragradient scheme with the viscosity approximation method. We prove a strong convergence theorem for the sequences generated by this new iterative process.   相似文献   
147.
This paper is concerned with the convergence analysis of the horizontal method of lines for evolution equations of the parabolic type. Following a semidiscretization in time by \(S\) -stage one-step methods, the resulting elliptic stage equations per time step are solved with adaptive space discretization schemes. We investigate how the tolerances in each time step must be tuned in order to preserve the asymptotic temporal convergence order of the time stepping also in the presence of spatial discretization errors. In particular, we discuss the case of linearly implicit time integrators and adaptive wavelet discretizations in space. Using concepts from regularity theory for partial differential equations and from nonlinear approximation theory, we determine an upper bound for the degrees of freedom for the overall scheme that are needed to adaptively approximate the solution up to a prescribed tolerance.  相似文献   
148.
In this work we investigate the performance of a simple, disposable electrochemical aptasensor for lysozyme and its usefulness for monitoring the allergen risk along wine production. The sensor relies on screen‐printed gold electrodes modified with gold nanoparticles as the electrochemical transducer, with detection by cyclic voltammetry. This simple method is characterized by a detection limit of 0.32 μg.mL?1 lysozyme and a linear range of 1–10 μg.mL?1, being appropriate for the analysis of lysozyme‐treated wines. Several white wines where sulphur dioxide was partially replaced by lysozyme were produced and analyzed with the aptasensor at critical stages during wine production. The results obtained with the aptasensor were moreover compared with those recorded in parallel by a standard method, high performance liquid chromatography (HPLC). The specific advantages brought by the use of nanomaterial and the limitations of the sensor are discussed. The sensor allowed evaluating the effect of various technological steps along wine production on the content of lysozyme.  相似文献   
149.
Journal of Thermal Analysis and Calorimetry - A simple synthetic method was developed to prepare 4[Agpy2ClO4]·[Agpy4]ClO4 in a low-temperature decomposition process of [Agpy4]ClO4. A detailed...  相似文献   
150.
We present the experimental study of a free-standing metallic guided-mode resonant structure, for bandpass filtering applications in the mid-IR wavelength range. Structure consists of a subwavelength gold grating with narrow slits deposited on a silicon nitride membrane. High optical transmission is measured with up to 78% transmission at resonance. Angularly resolved spectra are presented revealing Fano-type resonance.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号